The extraembryonic membrane that contributes to the formation of umbilical blood vessels is the
A) allantois
B) amnion
C) chorion
D) yolk sac
E) placenta

Question

Quizplus · Accepted Answer

The allantois is an extraembryonic membrane that contributes to the formation of umbilical blood vessels. It also functions in the disposal of waste and gas exchange in reptiles, birds, and some mammals. The amnion forms a fluid-filled sac that surrounds and protects the embryo/fetus, the chorion functions in gas exchange and nutrient transfer, and the yolk sac plays a role in early embryo nutrition. The placenta is a specialized organ that forms in the uterus during pregnancy, which provides oxygen and nutrients to the developing fetus and removes waste products.

The Extraembryonic Membrane That Contributes to the Formation of Umbilical